Seeded 16th, Williams is a three-time Key Biscayne champion, but her most recent title came in 2001. She's into the Key Biscayne quarterfinals for the first time since 2012.

Williams swung with her typical aggressiveness from the baseline, hitting 40 winners to nine for her fourth-seeded opponent. Williams also won 14 points at the net.

She improved to 7-0 against Wozniacki and is 4-0 this year against top-10 opponents. The 34-year-old Williams reached her first Grand Slam quarterfinal in five years at the Australian Open in January before losing.